British Prime Minister Boris Johnson plans to tell European Union leaders he will withhold 30 billion pounds ($37 billion) from the Brexit divorce bill unless they agree to changes to the deal, the Mail on Sunday reported.If Britain leaves the bloc without a trade deal, lawyers have concluded the government's will only have to pay the EU 9 billion pounds, rather than 39 billion pounds, the newspaper reported. This is because there will not be any of the costs associated with any transition period, the newspaper said.Johnson's office did not immediately respond to a request for comment.